CSP–520N–1
General
MD 520N (500N) ROTORCRAFT FLIGHT MANUAL
TM
Original
1–9
1–11. DESIGN AND CONSTRUCTION
The MD 520N helicopter is a 5 place, turbine powered, rotary−wing aircraft
constructed primarily of aluminum alloy while the tailboom and thruster are
primarily a graphite composite. The main rotor is a fully articulated five−
bladed system, with anti−torque provided by the NOTAR
system. Power from
the turboshaft engine is transmitted through the main drive shaft to the main
rotor transmission, from the main transmission through a drive shaft to the aft
transmission and through a second drive shaft to the NOTAR
fan. An over+
running (one−way) clutch, placed between the engine and main rotor t
sion permits free−wheeling of the rotor system during autorotation.
Airframe:
The airframe structure is egg−shaped and provides very clean aerodynamic
lines. The rigid, three−dimensional truss type structure increases crew safe+
ty by means of its roll bar design, and by reduction in the number of poten+
tial sources of failure. The airframe structure is designed to be energy ab+
sorbing and fails progressively in the event of impact.
The fuselage is a semi−monocoque structure that is divided into three main
sections. The forward section is comprised of a pilot compartment and, di+
rectly aft separated by a bulkhead, a passenger/cargo compartment. The pi+
lot compartment is equipped with seats for the pilot and either one or two
passengers. A canopy of transparent tinted acrylic panels provide excellent
visibility. The left seat in the pilots compartment (looking forward) is the
pilot’s seat (command position); in special military version helicopters, the
pilot’s seat is on the right side.
The lower fuselage structure beneath the pilot/passenger floor contains com+
partment space for the aircraft battery and provision for small cargo storage
or installation of avionics equipment. Access to the compartments is through
two floor door plates.
The cargo compartment in the center of the aircraft contains provisions for
installation of a bench or individual folding type seats for two passengers,
which are adjustable in height.
The aft section includes the structure for the tailboom attachment, NOTAR
fan and engine compartment. Access to the engine compartment is provided
through clamshell doors contoured to the shape the fuselage.
The lower section is divided by the center beam and provides a housing for
the two fuel cells. Provisions for the attachment of a cargo hook are located
on the bottom of the fuselage in line with the center beam.
Landing gear:
The landing gear is a skid−type attached to the fuselage at 12 points and is
not retractable. Aerodynamic fairings cover the struts. Nitrogen charged
